W3C mobileOK Checker

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Detailed report

1. Markup

   The quality of the markup sent to mobile browsers will impact the reliability and smoothness of the rendering of the page. Markup validity is the first step to delivering content that can be parsed and rendered reliably by browsers. The recommended markup format for mobile content is XHTML Basic 1.1. But beyond validity, various tags and attributes have a specific impact in the mobile world. For instance, CSS style sheets should be used to control the layout of the page instead of presentational tags (e.g. center, big, or font) and images sizes should be defined in the markup to avoid reflows.

   • [low] Either the height or width attribute is missing
     When the width and height attributes are not specified on an image, browsers need to reflow the page when the image has finished loading, which may disrupt the user experience.

     Add width and height attributes matching the actual dimensions of the image.

     Triggered by the resource under test:

     … <img alt="" src="http://im.banner.t-online.de/adserv/3.0/784.1/0/0/2/ADTECH;grp=0;alias=Telefonbuch_mobil_Startseite_mobileAd_class2;cookie=no;uid=no;misc=1259086772-c596c9957288a6f9945f6365113c8210"/>

     Related best practice:
     [IMAGES_SPECIFY_SIZE] Specify the size of images in markup, if they have an intrinsic size.
2. Images/Objects

   Images and/or image objects must be delivered in an appropriate format and dimensions so that they can be retrieved and rendered by most mobile browsers. mobileOK requires that all images and rendered objects be either GIF or JPEG images.

   • [critical] HTTP status code 404 (Not Found) or 5xx (Server Error) received for an embedded resource
     Embedded resources must be retrieved for the page to be correctly rendered.

     Check and fix the following link(s).

     Triggered by http://www.das-telefonbuch.de/img.fit/job-host-manager/6Uv_2SdmGdKOSZW065ZlJw.gif.
   • HTTP status code 3xx (Redirection) received and the HTTP Location header targets a relative URI
     Redirections should be avoided because of the usually high latency of mobile networks. Since the final URI of the resource is on the same server, server-based redirection may be possible and would save a round-trip between the server and the end user

     Triggered by http://mobtelbu.ivwbox.de/cgi-bin/ivw/CP/mobtelbu;S/,C//,D1259086772.
   • There is a small fully transparent image
     Requiring a user to download and render a completely transparent image does not bring any direct value to the user and slows down the loading of the page.

     Triggered 3 times by the resource under test.

     Related best practice:
     [GRAPHICS_FOR_SPACING] Do not use graphics for spacing.
   • There are more than one fully transparent images
     Requiring a user to download and render several different completely transparent images does not bring any direct value to the user and slows down the loading of the page.

     A single transparent image should be sufficent for tracking purposes. Is the duplicated image really necessary?

     Triggered by the resource under test.

     Related best practice:
     [GRAPHICS_FOR_SPACING] Do not use graphics for spacing.

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1. Structure of the page

   Markup validity does not ensure that tags are used appropriately. For instance, given the lack of support for nested tables in mobile browsers and the small screen sizes, using tables for layout will not work on mobile devices. The same goes with the use of applets, frames, pop-ups, and so on. The size of the page is also a very important aspect to keep in mind when designing mobile-friendly pages.

   1. Page weight

      The size of the page includes the page itself, the external style sheet(s), and the embedded images and objects. mobileOK requires the total size of the page to be under 20 KB, and the markup itself to be under 10 KB to ensure that the page can be retrieved and rendered by a mobile device in a reasonable amount of time.

      • There are more than 10 embedded external resources
        Loading the page requires a mobile browser to make more than 10 separate HTTP requests, which on some mobile networks can induce a delay of 10s or more before the page is shown to the user.

        Try to reduce the number of included resources (images and style sheets). For instance, style sheets can be merged together instead of being split across several files.

        Triggered by the resource under test.

        Related best practice:
        [EXTERNAL_RESOURCES] Keep the number of externally linked resources to a minimum.

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